Birding in Peru IV: Blue-mantled Thornbill

The Blue-mantled Thornbill belongs to the genus Chalcostigma in the subfamily Lesbiini. The genus is currently the subject of ongoing debate, with the South American Classification Committee (SACC) of the American Ornithological Society considering merging it into the genus Oxypogon.

The three subspecies of the Blue-mantled Thornbill

There are three recognized species of Blue-mantled Thornbill:

C. s. stanleyi: Found in Ecuador. Adult males have a sooty brown body with a bronzy green sheen on the crown and nape. The back reflects violet-blue, and the tail is steel blue. The gorget transitions from emerald green on the chin to pink and purple-violet at the lower edge. Adult females have only green under the chin, and the outer tail feathers are pale-tipped.
C. s. versigulare: Found along the eastern slopes of the Peruvian Andes and in the Cordillera Blanca on the western slopes. This subspecies differs in that the entire upperparts reflect deep violet-blue, and the gorget’s lower pink-to-violet color is narrower than in C. s. stanleyi.
C. s. vulcani: Found on the eastern Andean slopes from southern Peru to Cochabamba, Bolivia. This subspecies is similar to versigulare, but the lower part of the gorget is blue-gray or gray-violet.

All subspecies have a short, straight black bill and a small white spot behind the eye.

Habitat and Behavior of the Blue-mantled Thornbill

Elevation: Typically found at elevations between 3,000 and 4,200 meters (9,800 to 13,800 feet), though it has been recorded as low as 2,200 meters (7,200 feet) and as high as 4,500 meters (14,800 feet).
Terrain: Steep, rocky slopes and humid grasslands, with patches of Polylepis and Gynoxys woodland.
Feeding Behavior: Highly territorial when feeding. The Blue-mantled Thornbill primarily feeds on the nectar of small flowers, including Berberis, Gaultheria, Ribes, and Gentiana, as well as insects.

Source: https://en.wikipedia.org/wiki/Blue-mantled_thornbill and https://ebird.org/species/blmtho1/

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